When you only neck size every reload and only FL size when you need to, your not work hardening the body of the brass like you do if you FL size everytime. So ya, case head separation is minimized or delayed. Most of the time you will see the primer pockets weaken before case head separation happens. So your on the right track! As long as the case neck still gives you good bullet tension and the primers still seat tight your good to go. If the neck tension becomes an issue and the primer pockets are good, anneal the brass and keep going. Because your loads are hot just keep an eye on the case head and you should have no problems.

Of course there are always exceptions to the rule and I'm sure someone here will point that out!